There are known resin moldings integrally provided with an insert. Such a resin molding is formed by placing an insert of a shape corresponding to that of the resin molding in a mold, and injecting a molten resin into the mold.
When manufacturing such a resin molding integrally provided with an insert, the insert of a shape corresponding to that of the resin molding needs to be placed in a mold. Since the insert must be disposed at a predetermined position in the mold, the freedom of molding work is restricted.